#define _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>
#include <string.h>
#include <assert.h>

void My_strcpy(char* pb, const char* pa)
{
	assert(pa && pb);
	while (*pb++ = *pa++);
}

int main()
{
	char str1[20] = "hello world!";
	char str2[20] = { 0 };
	My_strcpy(str2, str1);
	puts(str2);
	return 0;
}